Pregelatinized starch is an effective and economical fluid loss agent in water based drilling fluids, which is a starch derivative. It is not bacterial degradation when at 120°C, environmentally acceptable and non-toxic. Modified Starch can produce a thin, LDick, tough fiLDer cake and promotes faster penetration rates with reducer friction. It can be used in all kinds of drilling fluid system. Pre-gelatinized starch is also sometimes "pregelatinized" to make them easier to dissolve during product manufacture. Modified starch is widely used in oil drilling, textile, paper and food industries.